Visual MODFLOW Flex

Groundwater Flow & Contaminant Transport Modeling Software

Visual MODFLOW Flex brings together industry-standard codes for groundwater flow and contaminant transport, essential analysis and calibration tools, and stunning 3D visualization capabilities in a single environment.

Why Choose Visual MODFLOW Flex?

Build models faster and more efficiently

  • Model inputs and grid design can be updated at any point in the modeling process as modeling objectives change, more data are collected and a better understanding of the sub-surface is achieved.
  • Modeling steps are conveniently presented in an intuitive, workflow-driven graphical user interface: see current and completed steps, and steps you need to finish.
  • GIS-based 3D conceptual modeling and numerical modeling all within a single integrated software environment. This reduces costly 3rd party pre-processing tools, and eliminates transfer errors.

Build larger, more complex credible models

  • Equipped to handle vast quantities of detailed, high resolution data. Simulate large and complex regional-scale groundwater systems.
  • Model inputs and outputs can be easily visualized alongside raw GIS field data in 3D, allowing credibility by demonstrating numerical model data generation (model layers, flow parameters, recharge data) from conceptual data (borehole logs, GIS data).
  • Unique design permits easy side-by-side comparisons of multiple models allowing you to assess alternative modeling scenarios, grid indiscretions and hydro-geologic interpretations.

Powerful Data Visualization

Built and designed on the latest in 3D visualization technology, Visual MODFLOW Flex allows you to effectively present and communicate your data to colleagues and stakeholders with impressive visual renderings of your hydrogeologic model.

  • Visualize all data, including conceptual objects, numerical grids, input data (property zones, boundary condition cells) and output data (calculated heads, pathlines, water table) in state-of-the-art 2D, 3D and multi-view (FlexViewer) displays.
  • Create cut-away and cross-sectional views that allow you to see inside your model.
  • Generate 3D animations and movies for reports or the web, and optimized OpenGL graphics for enhanced hardware rendering.
  • Add isolines, contours, pathlines and color shading to viewers.
  • Drape raster images (site maps, satellite imagery) over 3D surfaces to show relief

Efficiently Manage Multiple Models

Most modeling projects involve several scenarios/versions, e.g., steady-state vs transient, different properties, inputs and grid types. Visual MODFLOW Flex allows you to assess uncertainty and improve model credibility through comparisons and analysis of multiple modeling scenarios – all within a single project.

  • Manage multiple model scenarios in a single project, and make direct visual and numerical comparisons between different modeling scenarios.
  • Easily generate multiple models in parallel for evaluating alternative hydrogeologic interpretations and hypotheses.
  • Calculate head differences between multiple model runs, with the same or different grid size.
  • Compare and analyze multiple modeling scenarios for selecting the best, most realistic model.

Full GIS Integration

Easily construct your grid-independent hydrogeologic conceptual model in minutes using existing GIS data sets.

  • Quick and easy data importing of all common file types and formats.
  • Automatic coordinate system and units conversion on import, and automatic data validation and intelligent error checking on import.
  • Define model boundaries, property zones, boundary conditions and attributes from imported GIS data.

Integrated 3D Conceptual and Numerical Groundwater Modeling

Visual MODFLOW Flex provides a seamless transition from raw data through conceptualization to the numerical model all within a single intuitive modeling environment.

  • Define complex geology and model layers using borehole log data and cross-sections
  • Interpret GIS data to define hydrogeologic properties and boundaries independent of the grid
  • Run, analyze, and validate model results with raw data in 2D, 3D, and cross-section views
  • Easily create multiple conceptualizations; generate numerous grids and model scenarios in parallel all in a single project
  • Assess uncertainty though comparing heads from multiple model runs in 2D, 3D or chart views

Flexible Grid Options

Visual MODFLOW Flex provides various grid types from which you can generate your numerical model. Easily experiment with different grid types and choose the one that gives you the best, most stable model.

  • Choose from various structured and unstructured grid types to accommodate a wide range of applications and geologic conditions (e.g., pinch outs, discontinuities).
  • Improve simulation accuracy, reduce runtimes and increase model stability with unstructured grid types (MODFLOW-USG)
  • Easily generate multiple grids within the same project and compare side-by-side in 2D or 3D
  • Perform grid refinement around areas of interest
  • Create faster more stable models with nested child grids that contain local horizontal and vertical refinement (MODFLOW-LGR)
  • View all supported grid types 

Visual Modflow

What's New in Visual MODFLOW Flex 7.0

Experience the new version release of Visual MODFLOW Flex 7.0

Usability and Other Enhancements

Surface Water Modeling (SFR2)

Support for the Surface Flow and Routing (SFR2) Package in Finite Difference models:

  • New Surface Water workflow to develop and define connected networks of stream segments, diversions, and lakes
  • GIS editing capabilities for digitizing the surface water network including add, remove, edit, delete, snap, split, flip
  • Surface water network attribute editing dialog for streams and lakes
  • Translated SFR2 package including lake connections and 1-D vertical unsaturated flow beneath perched streams

Well and Multi-Node Well (MNW1/2)

Support for multi-node well (MNW1/2/I) packages in Finite Difference Models:

  • Dynamically switch between supported well models (WEL/MWN1/MNW2)
  • Import and edit well information including head loss, well skin, and pump constraint parameter supported in MNW1/2 packages
  • Support for non-vertical wells (also known as deviated or horizontal) wells:

  • Define conceptual Wells by drawing or by assigning wellhead points
  • Multi-select editing of well parameters and schedules


  • Import and/or set target residuals for Head/Concentration Observations
  • Display spatial distribution of residuals relative to target residuals by layer or observation group at the View Maps workflow step
  • The number of observations is included as a statistic below Calculated versus Observed calibration charts

Model Runs

  • Flow and Transport model run results are graphically displayed in real time including the global residual error and the max head/concentration change, as supplied by the active solver package settings.

  • Modified MODFLOW-USG to report solver progress in real time to the display console including global residual error

Model Import

  • When importing a MODFLOW model, you can now define an offset and rotation angle for the grid to set the model in world coordinates.
  • Import MODFLOW-NWT model and supported packages
  • When importing files MODFLOW files, invalid values that will cause issues during a simulation (such as negative conductivities) are replaced with project default values.

Usability and Other Enhancements

  • Visualize Flow Budgets/Fluxes for MODFLOW-USG simulations
  • When visualizing multi-attribute plugins (such as Flux, Velocity) to visualize you can select the active attribute to be shown in the view and in the status bar
  • Edit individual top/bottom of individual cells via the mouse or via script when editing grid layers
  • Graphically select refinement rows/columns using the mouse when editing the grid in plan view
  • A link to the model files is available at the Parameter Estimation step in PEST workflow
  • Translation log is copyable to the Windows Clipboard
  • NWT translation settings include option for the IPHDRY setting

Defects Addressed

  • Error during Visual MODFLOW Classic project import in projects with zero thickness cells when loading conductivity values
  • The selected background color was not included in exported images of 2D views
  • Property Zones listed in alphabetical order rather numerical order in the Edit Properties window
  • Style settings of polygon were not retained between sessions
  • Error “MS Office is not installed…” shows up during import occurs when certain versions of Office are installed
  • The internal handling of time units was refactored handle schedules and values with varying time units and scales with improved precision, accuracy, and consistency to within one second regardless of schedule duration and time units selected
  • Unable to enter negative model coordinates when defining a grid
  • In some cases, when reloading a project, the “Failed to move to target step” error appears
  • Voronoi grid not generated correctly when input features nearly coincide with the model boundary
  • Some dialog and workflow step buttons were missing/cutoff when using lower resolution display settings
  • Unable to edit/assign boundary conditions if the duration of the schedule too large
  • Background color was not saved between sessions in some views
  • The option to use shapefile attribute data to define conceptual property zones not functional
  • In some cases, errors prevented the export of calibration data
  • Unable to convert a conceptual model to USG when certain shapefiles are used to define the model domain
  • The option to use shapefile attribute data to define conceptual property zones not functional
  • Errors preventing MODPATH runs in 32-Bit Versions of Flex
  • Extract Subgrid failed if any model run under the original grid was previously deleted
  • In some cases, concentration observations were not correctly displayed at the View Charts step
  • Edit grid script failed when using shift model origin commands on variably refined grids
  • Head and concentration observations were not displayed due to translation errors in some SEAWAT models
  • Concentrations were not available in the Project Color Palette
  • In rare cases, the pumping schedule was not correctly translated in the WEL package
  • In some cases, the project could enter a state where it could no longer be saved due to the presence of larger shapefiles
  • In some cases, the RT3D simulation time was not correctly translated into the BTN package
  • Rerunning a model reset/removed the outputs selected in the cell inspector
  • Immobile concentrations were not correctly read on successful dual domain runs of MT3DMS or SEAWAT
  • PEST workflows did not correctly support overlapping zones in multi-layer models
  • In some cases, observations could not be read with a Wall BC was present in the simulation
  • In some cases, importing a 3D-gridded data object deleted certain property values in related numerical model(s)
  • Pilot Point values not correctly assigned in distributed models, particularly in Tikhonov Regularization
  • In some cases, very thin model cells in a Q-grid cause errors when converting conceptual model to a MODFLOW-USG workflow

Visual MODFLOW Flex Applications include

  • Delineate well capture zones for domestic water supply development
  • Design and optimize pumping well locations for mine dewatering projects
  • Determine contaminant fate and exposure pathways for risk assessment
  • Simulate surface water-groundwater interactions
  • Watershed scale/regional groundwater modeling, and aquifer storage and recovery (ASR)
  • Evaluate groundwater remediation systems (pump and treat, funnel and gate etc)
  • Evaluate saltwater intrusion

Get Started With Visual MODFLOW Flex